java - numeros - ¿Cómo encriptar un ZipOutputStream en Google appengine?

encriptar y desencriptar rsa en java

Question

Estoy creando archivos zip en GAE con Java, usando ZipOutputStream para subirlos a Google Cloud Storage.

Sin embargo, necesito encriptar los archivos, pero no sé cómo.

¿Alguien sabe cómo encriptar un ZipOutputStream en Google Appengine?

Answer 1

A continuación se muestra una aplicación Java de ejemplo que demuestra cómo escribir un bloque de texto en un archivo cifrado DES dentro de un archivo zip. El resultado de la aplicación:

CloudStorageZipCrypto GET starting.
Creating file...
File created.
Writing to file: /gs/writable:<snipped>
Wrote to, closed, and finalized the file.
Reading file contents...
READ: The woods are lovely and deep.
READ: But I have promises too keep.

Tenga en cuenta que también puede hacer esto en el orden opuesto: agregue el archivo al zip y luego cifre el archivo zip. Solo requeriría cambiar el orden de las secuencias de cifrado y zip. Aquí está el código fuente:

package com.jeffterrace.appenginetest;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.nio.channels.Channels;
import java.security.InvalidKeyException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.google.appengine.api.files.AppEngineFile;
import com.google.appengine.api.files.FileReadChannel;
import com.google.appengine.api.files.FileService;
import com.google.appengine.api.files.FileServiceFactory;
import com.google.appengine.api.files.FileWriteChannel;
import com.google.appengine.api.files.GSFileOptions.GSFileOptionsBuilder;

/**
 * Sample AppEngine Java class that reads and writes an encrypted, zipped file.
 */
public class CloudStorageZipCrypto extends HttpServlet {

  // Google Cloud Storage bucket name.
  private final String bucket = "jefftest1";
  // File name within the bucket.
  private final String filename = "test1.zip";
  // Text file within the zip file.
  private final String textFilename = "test1.txt.crypt";
  // The full Cloud Storage path for accessing the file from App Engine.
  private final String gsPath = "/gs/" + bucket + "/" + filename;

  // App Engine file service instance.
  private FileService fileService = FileServiceFactory.getFileService();

  // Secret key for DES encryption (only first 8 bytes are used).
  private final String secretKey = "thereisnospoon";

  @Override
  public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
    resp.setContentType("text/plain");
    resp.getWriter().println("CloudStorageZipCrypto GET starting.");

    resp.getWriter().println("Creating file...");

    // Create the GCS file and open it for writing.
    GSFileOptionsBuilder optionsBuilder = new GSFileOptionsBuilder()
      .setBucket(this.bucket)
      .setKey(this.filename)
      .setAcl("public-read");
    AppEngineFile gcsFile = this.fileService.createNewGSFile(optionsBuilder.build());

    resp.getWriter().println("File created.");

    resp.getWriter().println("Writing to file: " + gcsFile.getFullPath());

    // Open a write channel to the GCS object.
    FileWriteChannel writeChannel = this.fileService.openWriteChannel(gcsFile, true);

    // Initialize what we need for encryption.
    DESKeySpec dks;
    SecretKeyFactory skf;
    SecretKey desKey;
    Cipher cipher;
    try {
      dks = new DESKeySpec(this.secretKey.getBytes());
      skf = SecretKeyFactory.getInstance("DES");
      desKey = skf.generateSecret(dks);
      cipher = Cipher.getInstance("DES");
      cipher.init(Cipher.ENCRYPT_MODE, desKey);
    } catch (Exception e) {
      resp.getWriter().println("Error initializing crypto: " + e);
      return;
    }

    // Create a zip file output stream and add a text file to it.
    ZipOutputStream zos = new ZipOutputStream(Channels.newOutputStream(writeChannel));
    zos.putNextEntry(new ZipEntry(textFilename));

    // Write some text to the file, through a cipher output stream so it gets encrypted.
    CipherOutputStream cos = new CipherOutputStream(zos, cipher);
    PrintWriter out = new PrintWriter(cos);
    out.println("The woods are lovely and deep.");
    out.println("But I have promises too keep.");

    // Close all the things
    out.close();
    cos.close();
    zos.close();
    writeChannel.closeFinally();

    resp.getWriter().println("Wrote to, closed, and finalized the file.");

    // Open the zip file back up from GCS
    gcsFile = new AppEngineFile(this.gsPath);
    FileReadChannel readChannel = fileService.openReadChannel(gcsFile, false);
    ZipInputStream zis = new ZipInputStream(Channels.newInputStream(readChannel));

    // Read in the first file as UTF-8.
    zis.getNextEntry();
    try {
      cipher.init(Cipher.DECRYPT_MODE, desKey);
    } catch (InvalidKeyException e) {
      resp.getWriter().println("Error initializing crypto: " + e);
      return;
    }
    CipherInputStream cis = new CipherInputStream(zis, cipher);
    BufferedReader reader = new BufferedReader(new InputStreamReader(cis, "UTF-8"));
    resp.getWriter().println("Reading file contents...");
    String line;
    while ((line = reader.readLine()) != null) {
      resp.getWriter().println("READ: " + line);
    }

    // Close all the things.
    reader.close();
    cis.close();
    zis.close();
    readChannel.close();
  }
}